The Solar Maximum Mission (SMM) was launched on February 14, 1980 aboard Delta #151. The spacecraft was designed to investigate solar phenomenon. In its tenth month of operation, the spacecraft "blew" three hermetically sealed fuses in its atitude control system.

The Solar Max repair mission was launched on April 6, 1984 aboard shuttle Challenger and mission STS-41C. After deploying the Long Duration Exposure Facility (LDEF), the repairs to Solar Max could begin. The repairs to Solar Max were succesful. Due to changes to the shuttle manifest, NASA had to decide to either retrieve the Solar Max spacecraft or LDEF. When it was determined Solar Max would not be retrieved, engineering tests of the spacecraft were performed. Solar Max reentered on Dec 2, 1989.

The cover below was cancelled on the date of Solar Max's reentry in Greenbelt, Md. where GSFC is located. Goddard was responsible for the TDRSS system used to communicate with Solar Max to the end. I plan to put a cachet on the cover.